distribute	reads
0-500	192
500-800	17
800-1000	3
1000-1200	6
1200-1400	2
1400-1600	2
1600-1800	2
1800-2000	2
2000-2200	1
2200-2400	0
2400-2600	0
2600-2800	0
2800-3000	2
>3000	6
